1. Field of the Invention
The invention concerns an index shifter for a bicycle transmission. The index shifter has a housing which encloses a handle bar. A notch element with notches is mounted on a pivot within the housing and has a control cable to operate the bicycle transmission. A notch spring or detent spring is placed between the casing and the notch element, The notch spring is located in a recess of the housing, which recess has end stops to limit the motion of the notch spring.
2. Background Information
European Patent No. 0 676 325 A2 describes a known index shifter which shows a notch spring that consists of spring band material and has an asymmetric shape so that it can act in concert with the notches of a notch element through a projection or nose. The projection or nose is placed at the end of a spring arm that leads off from a side end, which side end is connected with the opposite end through an extended and arched bow. This enhanced spring design has advantages over a known plastic spring disclosed in FIG. 1 of European Patent No. 0 676 325 A2. However, the improved spring has the disadvantage of making more noise than the known plastic spring during shifting. The unfavorable properties of plastic, such as deforming under external forces through its creep properties in the course of time, however, are characteristic of the plastic spring.